This invention relates generally to a cooling fan drive system and, more particularly, to an arrangement of components of the cooling fan drive system.
Internal combustion engines include cooling fan drive systems. The cooling fan drive systems cool the internal combustion engine, and may also be used to drive components of either the internal combustion engine or a machine which is powered by the internal combustion engine. The machine may include, for example, power generation sets, earth working machinery, paving machinery, load transfer carrying machinery and the like.
The cooling drive assembly may be based on a hydraulic system. In these systems, four hydraulic pumps are typically connected to a hydraulic tank. The pumps suction hydraulic fluid from the hydraulic tank in order to perform the specific function of the pump. These pumps are positioned proximate to the associate component performing the specific function regardless of the position of the hydraulic tank. For example, an implement pump will suction hydraulic fluid from the hydraulic tank in order to drive the many components of the machine such as, for example, the steering mechanism. Similarly, a charge pump will suction hydraulic fluid from the hydraulic tank in order to xe2x80x9cchargexe2x80x9d an all wheel drive (AWD) pump. The AWD pump is used to drive wheels of the machine in either a forward or reverse direction and is positioned on a front side (e.g., a forward side of an articulation joint of the machine) of the machine closest to the wheels which are driven by the AWD pump. The cooling drive assembly also includes a cooling tank used to cool the hydraulic fluid prior to being returned to the hydraulic tank.
However, it is impractical and in some instances impossible to supply hydraulic fluid to the charge pump from the hydraulic tank. This is mainly due to a design of the internal combustion engine and the arrangement of the components thereon. For example, the internal combustion engine may be designed in such a manner that the hydraulic tank is mounted on a front portion of the machine while the charge pump must be mounted on an opposing and remote side of the internal combustion engine. In this case, a hydraulic line may not be able to be economically positioned and thus connected between the charge pump and the hydraulic tank. Also, the hydraulic line may be able to connect the charge pump and the hydraulic tank, but the charge pump would not be able to provide enough suction to force the hydraulic fluid from the hydraulic tank through the hydraulic line and into the charge pump. In any event, the hydraulic system cannot then be efficiently used to operate components of the machine.
U.S. Pat. No. 4,433,648 to Leblanc, which was issued on Feb. 28, 1984, shows an engine cooling system. The engine cooling system includes a fan and a fan motor as well as other components mounted thereon. Due to the design of the internal combustion engine, the fan motor is a belt driven motor. Also, due to design constraints of the internal combustion engine, there are no hydraulic components for changing or controlling the direction of the machine or for many various other functions.
The present invention is directed to overcoming one or more of the problems as set forth above.
In one aspect of the present invention a cooling fan drive system has a hydraulic tank that stores hydraulic fluid. A cooling fan pump is connected between the hydraulic tank and a cooling fan motor. A connector is connected between the cooling fan motor, the charge pump and the hydraulic tank. This arrangement allows the flow of hydraulic fluid from the cooling fan motor to the charge pump.
In another aspect of the present invention an internal combustion engine has a cooling fan drive system. The cooling fan drive system has a hydraulic tank for storing hydraulic fluid. An implement pump is connected to the hydraulic tank, and a cooling fan pump is connected between the hydraulic tank and a cooling fan motor. A filter is connected to the cooling fan motor and a connector is connected between the filter, a charge pump and the hydraulic pump. In this manner, the hydraulic fluid can flow from the cooling fan motor to the charge pump. An all wheel drive (AWD) pump is connected to the charge pump.